Police have warned people to avoid an area of Yeovil near the cinema after they found white powder early this afternoon.
The unidentified powder is believed to have been found in an envelope in a car park off Middle Street, beside Wilkinsons.
It is thought the envelope was then opened in an office in the Wilkinsons store, which has been closed this afternoon while emergency services investigate.
"Earlier this afternoon we were informed that an envelope containing white powder had been opened in a private office in the Wilkinsons store in Yeovil town centre," said an Avon and Somerset Police spokesman.
"The office has been isolated and the store closed.
"The emergency services have put into place well-rehearsed plans for dealing with these incidents.
"There is no threat to the wider public but the shop has been closed as a precaution with public safety our primary concern."
Police are appealing for anyone with information about the powder to call them on 101.
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